Motor vehicle key signaling device



P 7, 1953 5. SWEET MOTOR VEHICLE KEY SIGNALING DEVICE 2 SHEETS-SHEET 1Filed Jan. 31, 1951 BUZZER INVENTOR.

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ATTOR/Vi/J Patented Apr. 7, 1953 UNITED STATES PATENT OFFICE 4 Claims.

1 This invention relates to warning devices for motor vehicles andparticularly to an electric signalling system for informing the operatorof the existence of certain undesirable conditions of the motor vehicle.

An important object of the invention is to provide a motor vehiclesignalling device for indicating certain undesired conditions of thevehicle and particularly to notify the operator of certain conditionsrespecting the ignition key or the emergency brake. This invention isparticularly adapted for warning the operator of a motor vehicle of theretention of the key in the ignition switch when the motor vehicle isnot operating under its own power and the application of the emergencyhand brake when the vehicle is operating under its own power. Anotherimportant object of the invention is to provide an improved electricsignalling system containing control elements operatively associatedwith either the ignition switch or the emergency brake or both andincluding means in novel association therewith which is responsive tothe operation of the engine of the motor vehicle for imposing asupervisory control over the circuit. A further important obiect of theinvention is to provide a signalling or warning device of this characterwhich is capable of being produced at low cost and quickly andeconomically installed in a motor vehicle with very little if anymodification of the structure thereof.

In carrying out the invention, the device comprises an electric circuitincluding control elements associated with the ignition key and with thehand or emergency brake and further including a master switch mechanismcontrolled by the engine and capable of varying the operation of thecircuit depending upon whether the engine is functioning or not. Onecontrol element of the circuit is mounted adjacent to the ignitionswitch of the motor vehicle, preferably on the instrument paneL'andarranged to engage the ignition key inserted therein. Another controlelement of the circuit, is associated with the hand brake and adapted tobe moved to closed position when the handbrake is applied. Separatebranch circuits are provided for the two control elements which lead toa single alarm or warning indicator. Common to the two branch circuitsis a master switch control. which is operatively connected with theengine. of the motor vehicle and is responsive theretoto control the twobranch circuits and the operation of the warning indicator. The masterswitch control is preferably operated by differential pressures createdby the engine. It is preferred, from the point of economyand-convenience of installation, to use a pressureresponsive devicewhich is connected into the-air intake of the engine and is responsiveto the differential air pressures developed by the engine.

A feature of the invention is the provision of an improved controldevice associated with the ignition switch and capable of beinginstalled and operated Without altering the construction of the switch.Another feature of the invention is the provision of means for enablingthe operator at any time to adjust at least one of the control elementsin order to render theparticular branch circuit associated therewithinoperable.

Various other objects, advantages and meritorious features of theinvention will become more fully apparent from the followingspecification, appended claims and accompanying drawings wherein:

Fig. 1 is a schematic view of the electric circuit showing controldevices associated with the ignition key and the hand brake and alongitudinal sectional view through an engine responsive master switch,

Fig. 2 is a vertical sectional view taken through the control deviceassociated with th ignition switch showing in full and dotted outlinecertain positions of the parts thereof,

Fig. 3 is a vertical sectional view taken along line 3-3 of Fig. 2,

Fig. 4 is a schematic view showing a modified form of ignition switchcontrol device and its-association with an engine responsive masterswitch,

Fig. 5 is an enlarged longitudinal sectional View through the ignitionswitch control device of Fig. 4,

Fig. 6 is a sectional view through the ignition switch control device ofFig. 5 and taken along line 65 thereof,

Fig. 7 is a perspective view of the stationary part of the ignitionswitch control device shown in Figs. 4; to 6, and

Fig. 8 is a perspective view of the movable part of the ignition switchcontrol device.

In the embodiment of the invention illustrated in Figs. 1, 2 and 3, theouter face of the ignition switch is shown at It and illustrated indotted outline is an ignition key 12 having one end inserted into theignition switch and the other or handle end projecting outwardly awaytherefrom. The ignition switch may be of the conventional type includinga rotatable barrel having a slot for receiving the inserted end of theignition switch. When the proper key is inserted into the ignitionswitch, the key together with the barrel brake.

may be rotated from an off position to an on position and return. In theon position, the engine of the motor vehicle may be started andoperated, and in the off position, the ignition circuit will be cut offand also the operation of the engine.

Associated with the ignition switch and preferably electricallyconnected thereinto by engagement with the ignition key is a controlelement generally indicated at i i in Figs. 1, 2 and 3. The controlelement is preferably attached to the outer or front side of theinstrument panel immediately adjacent to the ignition switch such asbeing disposed therebelow as shown in Fig. 1. The switch element Hiincludes two similarly formed contact members 13-45 whichare arranged tocontactually engage the'outer end of the ignition key for closing abranch circuit hereinafter described. The switch element 1 includes abody is which as shown may be of a -;hen1ispherical shape and attached.to the instrument panel to below the ignition switch. The body ispreferably formed of insulated material such as a molded plasticcomposition.

.A :control element generally indicated at 22 .in Fig. ,1 is associatedwith the hand or emergency Motor vehicle emergency hand brakes usuallyhave a pull rod such as that indicated at 24 which may extend throughthe instrument panel 2t as shown or supported by any suitable meanstherebelow. 'The control element 22 comprises two contact members 25 and23 which are arranged to engage one another and close a branch circuithereinafter described when the hand brake is moved to brake applyingposition.

A master control element is generally indi- ,cated at '38 in Fig. 1 andincludes make and break switches for opening and closing the two branchcircuits. The master switch is operatively connected to the motorvehicle engine, shown in small .scale at 32, and is responsive to theoperthe windshield wipers.

Associated in the circuit is a warning or alarm indicator generallyshown at 38. This indicator .may be a :conventiona1 electric buzzeradapted when energized to emit a sound. The indicator may be of anysuitable design for this purpose and in lieu of emitting a sound may beconstructed to flash a warning light on the instrument panel. Thecontrol circuit including the buzzer apparatus is electrically energizedto any suitable source such as the motor vehicle battery indicated at40.

The general arrangement of the parts of the embodiment of the inventionillustrated in Figs. 1 to 3 has been set forth hereinabove. Theseinclude the two control elements I and 22 associated respectively withthe ignition switch and the emergency brake of a motor vehicle, a master1 control element 35 operatively associated with theengine of the motorvehicle, and the warning indicator 38 to advise the operator of anyundesired operationa-l condition of the vehicle. The

. control element It for the ignition switch and its associated branchcircuit is designed to indicate any accidental r'etentiongo'f the key inthe ignition switch after the engine hasjcea'sed to operate andparticularly to prevent the'operpanel to. insulating element ie in theform .of a grommet hole, as is evident in Fig. 3.

d ator from leaving the vehicle with the key in the ignition switch. Thecontrol element 22 for the emergency brake is designed to indicate anyaccidental application of the hand brake during the operation of thevehicle and particularly to prevent the operator from driving thevehicle with the hand brake applied.

The body it of the ignition switch control element it is mounted on theinstrument panel such as by means of a bolt 42 whichserves part of thebranch circuit with which the two contact members l d-l6 are associated.For insulation purposes, an aperture or hole in the panel through whichthe bolt 42 extends is made larger than the diameter of the bolt inorder to receive insulating material between the bolt and the edge ofthe hole in the panel. For this purpose, the inner fiat side of the bodyl8 may abut or have secured thereto a sheet .54 of insulating materialhaving a circular ridge 46 which extends part way through the hole inthe On the back side of the panel is an which likewise projects part wayinto the bolt hole. The circular ridge 4t and the grommet .3 complementone another and function to centrally space the bolt from the edge ofthe The bolt projects beyond the insulating grommet 58 and securedthereto the terminal'end 59 of an electric conducting wire A nut E lcompletes the assembly and as shown Fig. 3 not only functions'to holdthe body 1 8 on to the front side of the panel but also to clamp theterminal end '56 to the wire 52 against a washer 56 to form anelectrical connection with the bolt.

The opposite end of the fastening bolt 42 is threadedly received in oneend of a member 58 of electric conductive material. The member v58 mayassume the formation shown in Figs. 2 and 3 and asevident from thesefigures it ismounted within the body 13 as in insert. The opposite orupper end of the member 58 projects into agenerally V-shaped slot-60which .opens in the direction of the key l2. The two contact members orfingers iii-l5 extend into this slot and downwardly along the oppositeside of the member 58 as shown in Fig. 2. Extending inwardly fromopposite sides of the body iii are two similarly formed axially alignedpins 82-52, the inner ends of each of which are reduced and threaded asshown .to engage the member 58.

beret and the bolt '32 to which it is joined.

The contact fingers Iii-i5 are preferably formed of resilient materialsuch that they may be readily bent out of their normal position andreturned to such position when pressure is relieved. The two fingers arepreferably slightly spaced apart from one another'and are so disposedwith respect to the key slot of the ignition switch that when the key i2is inserted thereinto it slides between the fingers while maintainingcontact therewith. In Fig. 2, the vertical I position of the key and thedotted positions of the fingers Iii-l5 immediately adjacent to theopposite sides thereof show the relation of these parts of one anotherwhen the key is first insert- 'ed into the ignition switch prior to theturning thereof to engine operating position When the key I2 is turnedto engine operating position, such as in a clock-wise direction to theinclined position shown in Fig 2, the two fingers I6I6 are spread aparttherebv to the full line position shown in Fig. 2 while continuing tomaintain contact with the key. A similar relationship will occur if thekey is turned in the opposite direction.

Although the control element I4 and its contacting fin ers l 6-I6 areshown as being applied to an ignition key of the character that wheninserted in the ignition switch it extends in a vertical plane and isturned to an inclined position to close the i nition circuit of theengine. it is understood that the control element may be suitablymounted to have its fin ers engage an igntion key which operates in anyother manner to turn on and ofi the ignition circuit Each finger I6 ofthe control element I4 is preferably insulatively sheathed for the ma orportion of its length. The sheathing of each finger is preferablydivided into two separate sections 64 and 66 enclosing difierentportions of the finger and end abutting one another. Overlappinglyencircling the abutting ends of the two sections of the sheath is arelatively tightly wound coiled wire 68. The coiled wire together withthe two sections of the sheath will hold the finger in any manuallyadjusted position relative to the key and will enable the operator toshift either one or both of the fingers completely out of contact withthe key if it is desired to temporarily discontinue the operation of thecontrol element I4. One position to which the fingers may be adjusted tobreak contact with the key is shown in dotted outline by lifting fingerI6 of Fig. 2. When it is desired to return either one or both fingersfor engagement with the key, the operator can easily bend the sheathedportions of the finger inwardly toward the key for contact therewith.

The control element 22 for the emergency or the hand brake has beenpreviously described as including two contact members 26 and 28 whichare brought into engagement with one another to close a branch circuitwhen the hand brake is pulled to brake applying position. One contactmember, such as 26, is mounted in any suitable manner on the control rod10 of the hand brake, such as by means of a pair of c amping members12-12 which secure a post I4 to the rod 19 for joint travel therewith.The contact member 26 is mounted on one extremity of the post 14 and isinsulated therefrom by means of a sheet or disc of insulation indicatedat 16. The other contact member 28 is similarly insulatively mounted ona short post 18 which is yieldingly projected toward the contact member26 by means of a coiled spring 86. One end of the v coiled springencircles the post 78 and is stated thereon and the other end of thespring encircles a short post or stud 82 fixed to the panel 20 or othersuitable support structure of the vehicle. As shown in Fig. 1, the endof the spring opposite to the contact member 28 is seated against thepanel 20 and mounted in this manner yieldingly urges the contact member28 inwardly from the panel and toward the contact member 26. It isevident that when the handle 84 of the hand brake is pulled outwardlyrelative to the panel 20 that it will bring the contact member 26 intoengagement with the contact member 28.

The motor vehicle battery 40 or other source of electrical energy has alead wire extending therefrom which is divided at 88 into two branchcircuits 90 and 92. One branch circuit, such as 90, extends to the innerend of the ignition switch and is connected thereto. This branch circuitmay be usual lead wire from the battery for conducting electricalcurrent to the ignition switch. The other branch circuit 92 extends toone of the switch members of the control element 22, such as the contactmember 26, as indicated in Fig. 1. Leading from the other contact member28 of the control element 22 is a lead wire 94 which forms the balanceof the branch circuit 92 and is joined thereto when the two contactmembers 26 and 28 engage one another.

The master control element is operated from the engine 32 ashereinbefore mentioned and preferably is constructed to function inresponse to pressure changes in the air intake of the manifold. Soconstructed, the master control element 30 comprises in general acylinder 96 in which reciprocates a piston 98 having a control rod I00.The cylinder 96 may be in the form of a tube of transparent plasticmaterial rendering the inner parts thereof visible to the operator. Oneend of the cylinder 96, such as the lower end thereof as illustrated inFig. 1, may be provided with a closure plug I02 having an externallythreaded part I04 threadedly engaging the inner surface of the tube toform an airtight joint therewith. Forming part of the plug I62 is afitting I66 to which one end of the conduit 34 is connected. Aspreviously described, the conduit 34 is connected to a pressure varyingpart of the engine, such as the intake manifold or a vacuum operatedwind-shield wiper.

Extendin cross ise of the cylinder 96 is a support I08 which may beformed of molded plastic material. This support is axially bored to forma guide for the rod I00 of the piston and also serves as a seat for acoiled spring II 0. The end of the rod I00 opposite to the piston 98 isprovi ed with a head spring III! seats. The relat onship of the springto the p ston is su h that it yieldingly urges the piston away from theend of the cylinder to which the conduit 34 is connected. The spring IIOoperates in a direction reverse to the influence of the vacuum createdby the operation of the engine and is of such a tension that when theengine is operated the vacuum created thereby will overcome the tensionof the engine and draw the piston downwardly toward the plug I02. Theend of the cylinder 96 opposite to the plug I62 is closed and tightlysealed by a plug H4 which is of insulated material and may be formed ofmolded plastic. 7

Associated with the pressure respons ve device 39 are make-and-breakswitches for opening and closing a control circuit to the indicator 38.As shown in Fig. 1, the plug I I4 is provided with an electric terminalH6 in the form of a bolt which axially projects therethrough and intothe interior of the cylinder 96. This terminal is adapted to be engagedby switch I I2 as is evident in Fig. 1. Mounted in the side wall of thecylinder 96 and closely adjacent to the terminal H6 is a contact memberI I8 of electrically conductive material. This contact member is mountedby means of a nut and bolt assembly indicated at I20 so as to be engagedby the switch I I2 of the piston when thelatter is abut- II 2 againstwhich coil ting the terminal IIE. Leading from the bolt connection I20is a wire I22 which extends to one of the terminals 124 of the indicator38. It is evident from Fig. 1 that when the eng ne ,isnot operating,the'spring III] will shift the piston toward the terminal I I6 bringingthe head 'I'I2 into contact simultaneously with the terminal andthe'contact member I I8 and electrically connecting the wire 52 leadingfrom the ignition switch control element I4 with the wire I22 leading tothe alarm indicator 38. However, when the engine is operated, the vacuumcreated'thereby will draw the piston toward the conduit 34 and break thecontact of the switch II2 with the terminal I I thus interrupting thecircuit to the indicator 38. It is thus apparent that engine beingoperated. The operation of the buzzer 38 or other form of indicator willadvise the operator that he should remove the igntion key before leavingthe vehicle unattended. If it is the desire of the operator to retainthe key in the ignition switch in the off position, he may spread thefingers IB-I5 apart suiflciently to break their contact with the key andthus interrupt the circuitto the buzzer.

Also carried by the master control element is a make-and-break switchconnecting the emergency brake control element 22 with the alarmindicator 38. Thi make-and-break swit h may consist of two similarlyformed electrical contact plates I 26I26 disposed, as shown, in theinterior of the cylinder 98 and diametrically opposed to one another.Suitable nut and bolt assemblies 528 may be provided for mounting thesecontact plates in the interior of the cylinder. Carried by the rod orplunger I65 of the iston is a cross member I38 of electricallyconduct've material which when disposed between the two plates I25-I2$will simultaneously engage the same and serve to electrically connectthe two plates together. The contact memberIBIl carried by the pistonoperates in reverse to the head II2 thereof and when the engine is notoperating it assumes a position out of contact w th the plates asindicated in full line in Fig. 1, but when the en ine is in operation itwill be drawn be tween the two plates and into engagement therei with asshown in dotted outline in Fig. 1.

The lead wire $4 from the contact member 23 of the control element 22 isconnected to one of the plates [26-426 as shown in Fig. 1. The othercontact plate I25 is connected by means of a wire I32 with the lead wireI22 extending to the indicator 38.

It isevident from the relationship of the parts in Fig. 1 that if thehand brake should be applied While the engine is in o eration a completecircuit will be established between the battery 66 through the contactmembers 26 and, 28 and the plates I26I26 to the alarm indicator 38. Inthese circumstances, the buzzer or other form of indicator will informthe operator that the hand brake is in applied position while the engineis in operation. This will prevent the operator from driving the vehiclewith the hand brake applied.

Figs. 4 to '8 inclusive illustrate a modification of-the invention andparticularly that part relating to the ignition switch control element.In lieu of the fingers I6-I5 which project toward the i nition key forengagement therewith, the modification provides an assembly of partswhich is mounted directly over the outer face of the ignition switch andis secured to the panel in overlying relation thereto. As shown in Fig.4, a conventional ignition switch body is indicated at I 34 projectingrearwardly from the instrument panel 213. The body I34 is prov'ded witha front plate I35 which has a larger diameter than the body I34 andabuts the front side of the panel in the manner indicated in Fig. 4. Abattery, such as the motor vehicle battery All, is connected by leadwire I38 to the ignition switch. Also associated with the ignitionswitch control is an engine operated control device generally indicatedat Hi9 s milar to the control element previously described and an alarmindicator i the form of a buzzer I42.

Overlying the front plate I 36 of the ignition switch is an assembly ofparts illustrated in Figs. 7 and 8. One of these parts consists of aring I l-t of insulated material such as molded plastic having aninwardly projecting circularly formed flange M 6. The inner diameter ofthe ring I44 is such that it may encircle the front plate I36 of theignition switch and have the end thereof opposite to the flange abut theouter side of the panel 26. The circular flange I 56 is of less diameterthan the front plate I36 and partially overlies the same in spacedrelation thereto as is evident in Figs. 4 and 5. The ring I44 is securedto the front side of the panel 20 either by adhesion or by the provisionof short similarly formed studs hid-I 58 which may be integrally moldedtogether with the ring and project from the inner end thereof in themanner shown in Fig. '7. For the reception of the studs I l8-Ii8 thepanel 26 is provided with holes disposed on the opposite ides of thefront plate I35. Suitable screws I50 together with washers I52 arethreaded in bores in the studs 38 and mount the ring on the front sideof the panel in a manner which is clearly shown in Fig. 5.

The other part of the assembly overlying the front plate I of theignition switch consists of a rotatable member I54 of insulatingmaterial such as molded plastic. As shown in Fig. 8, this member is of acircular formation having such a diameter that it may be received insideof the ring Hi l and between the flange I46 thereof and the front plateI36 of the ignition switch. The rotatable part I5 3 is provided with acentrally located projecting boss I56 of circular formation which whenassembled inside of the ring I44 projects through the reduced opening ofthe flange I 25 and extends substantially flush with the outer facethereof. Formed in the boss and also extending through the main bodyportion of the part I54 is a key slot I58 through which the ignition keyI2 is inserted and removed.

Carried by the stationary ring I64 of the assembly is an electricalcontact member I which, as shown in Figs. 6 and 7, is mounted so thatone side thereof opens through the inner wall of the ring and conformsto the curvature of the inner peripheral surface thereof. The contactmember I59 is preferably secured in the ring I44 by one of the screwsI513, as shown in Figs. 5 and 6.

Carried by the movable part or circular disc Hi l of the assembly is anelectrical contact mem ber I82 which, as shown inFigs. 6 and'8, has oneface thereof which opens through the outer peripheral surface of thedisc for engagement'with the contact member I60. The engaging face ofconform with the curvature of the contact member I60 so that when theinner movable part I54 is rotated the contact member I62 will slide orwipe across the exposed face of the contact member I60.

The contact member I62 of the movable part I54 is electrically connectedwith a key engaging eleinent-I64disposed s as to expose one side thereofin the key slot I58. The two contact members I62 and I64 of therotatable part are preferably electrically connected together by a flatstrip or blade of electrically conductive material I66 which extendsbetween the two contact members and has its opposite ends in engagementtherewith. In order to prevent wear of the contact members fromaffecting the electrical connection-therebetween, it is desired to placethe blade I66 under tension, such as by bowing the same, as shown inFig. 5, and by providing a radial passage I68 in the part I54 of a sizeto accommodate any flexture of the blade. In such a construction, it isdesired to have the opposite ends of the blade I66 secured or fixed tothe contact members I62 and I64 to form a unitary assembly of theseelements. It is evident that the blade will yieldingly urge either orboth of the contact members I62 and I64 outwardly from the opposite endsof the passage I68.

The control element I40 previously mentioned is constructed similar tothe master control element 30 hereinabove described and includes acylinder I10, a piston I12, a piston rod I14, and a head I16 on the endof the rod I14 opposite to the piston. The piston end of the cylinder Iis provided with a closure plug I18 to which a conduit I80 leading to avacuum operated part of the engine is connected. The opposite end of thecylinder I10 is closed and is provided with a terminal in the form of abolt I82 which projects through the end of the cylinder and is adaptedto be engaged by the head I16 in a manner previously described inconnection with Fig. 1. Projecting through one side wall portion of thecylinder I10 is an electrical contact member I84 which is also adaptedto be engaged by the head I16 when the latter is in engagement with theterminal I82. A spring I86 similar to spring IIU yieldingly urges thepiston assembly toward the terminal I82 to bring the head I16 intosimultaneous contact with the terminal and the contact member I84.

The contact member I66 of the stationary part or ring I44 iselectrically connected with the terminal I82 by means of a lead wireI88. The result is that when the key I2 is inserted into the ignitionswitch it closes a circuit from the battery 40 through the key to thecontact member I64 and thence through the blade I66, contact members I62and I60 and through the control element I40 to the alarm indicator. Suchcircuit will be closed when the engine is not operating and the key isleft in the ignition switch. During the operation of the engine, thevacuum created thereby will overcome the tension of the spring I86pulling the piston toward the plug I16 and breaking the circuit bydisengaging the head I16 from the terminal I82. Removal of the key I2will, of course, also break the circuit from the battery to the buzzer.

In addition to serving as a warning to the operator that he is leavinghis key in the ignition switch when the engine is not operating, thedevice may be also used as an alarm to the operator in the event theengine ceases operating when he desires it to continue operating forrelatively long periods of time. Operators, such as those using longdistance freight hauling vehicles, quite frequently park the vehicle onthe side of the road and in cold weather operate the engine to keepthemselves warm as they sleep. In such circumstances, the alarm devicewill commence operating in the event the engine should stall during suchuse and advise the operator that the engine has ceased to operate.

What I claim is:

1. In a motor vehicle having an engine, a key controlled ignitioncircuit, and a hand brake; a signalling circuit including an alarmdevice operatively associated with the ignition circuit and with thehand brake and operable upon insertion of the key in the ignition switchto close the circuit to the alarm device and upon the application of thehand brake while the engine is operating to close the circuit to thealarm device; a master switch in said signalling circuit for governingthe operation of the signalling circuit; and means responsive todifferential pressures created by operation of the engine for actuatingsaid master switch.

2. In a motor vehicle having an engine, an ignition circuit including akey-operated ignition switch, and a hand brake; an electrical alarmdevice; a signalling circuit connected to the alarm device and to theignition switch and operable when the key is in the ignition switch tocause the alarm device to function; a separate signalling circuitconnected to the alarm device and to the hand brake and operable whenthe hand brake is applied to cause the alarm device to function; and amaster switch common to said signalling circuits and movable to twopositions; means associated with said master switch and operable whenthe same is in one of said positions to close the first signallingcircult when the key is in the ignition switch; means associated withthe master switch and operable when the same is in its second positionto close said second signalling circuit when the hand brake is applied;and means operatively connected to the engine and responsive to theoperation or non-operation thereor ior causing the master switch to moveiroin one to the other of said positions.

3. in a motor vehicle having an engine, an ignition circuit including akey-operated ignition switch, and a hand brake; an electrical aiarmdevice; a signaiiing circuit connected to the aiarm device and to theignition switch and 0peraoie when the key 15 in the ignition switch tocause the aiarm device to Iunction; a separate signalling circuitconnected to the aiarm clevicc and to the hand brake and operable whenthe hand brake is appiied to cause the aiarm device to iunetion; amaster switch common to said signalling circuits and movabie to twopositiohs; means associated with said master switch and operable whenthe same is in one or said positions to close the hrst signallingcircuit when the key is in the ignition switch; means associated withthe master switch and operable when the same is in its second positionto close said second signalling circuit when the hand brake is appiied';and means responsive to differential pressures created by the operationor the nonoperation or the engine and adapted to cause the master switchto move to the position to close the hand brake signalling circuit whenthe engine is operating and adapted to cause the master switch to moveto the other position when the engine ceases tooperate, to close theignition.

switch signalling circuit.

4. In a motor vehicle having an engine to drive the same, a key operatedignition switch for controlling the ignition circuit of themotorvehicleengine, a hand operated brake. forretarding movement of themotor vehicle, a signalling circuit including an alarm deviceelectrically associated with the ignition switch and with the.

hand brake and operable when the key is in the ignition switch to causethe alarm device. to function and likewise operable when the hand brakeis applied to cause the alarm device to function, means independent ofthe ignition switch and the hand brake for rendering the alarm deviceeither operable or non-operable, and-means operatively associated-withthe engine of the motor vehicle and responsive thereto to render thealarm device operable when the handbrake is applied whilethehenginetis-zon-u. erating and to render thehalarmcdevice; operable.when the key for the ignition switch is retained.

therein after the, engine ceasesnto operate;

SAMUEL SWEEE REFERENCE-591T??? wi e erenc re; i se rfiz e hel 10 file ofthis patent:

UNITED STATES Number Name Date I 1,737,774 Sherwood Dec. 3.192%};1,774,801 Macke et' al. S ept $19397 2 x 2 Ga l d 4124;;

FOREIGN PATENTS; Number- Country Date 0 32 G e t, r a c-r-v- 099;: 29:

